72828721 has 4 divisors (see below), whose sum is σ = 83232832. Its totient is φ = 62424612.

The previous prime is 72828683. The next prime is 72828761. The reversal of 72828721 is 12782827.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72828721 - 2⁹ = 72828209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72828761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5202045 + ... + 5202058.

It is an arithmetic number, because the mean of its divisors is an integer number (20808208).

Almost surely, 2^72828721 is an apocalyptic number.

It is an amenable number.

72828721 is a deficient number, since it is larger than the sum of its proper divisors (10404111).

72828721 is a wasteful number, since it uses less digits than its factorization.

72828721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10404110.

The product of its digits is 25088, while the sum is 37.

The square root of 72828721 is about 8533.9745136718. The cubic root of 72828721 is about 417.6067992641.

The spelling of 72828721 in words is "seventy-two million, eight hundred twenty-eight thousand, seven hundred twenty-one".